1. Field of the Invention
The present invention relates to a washing machine, and more particularly to a washing machine incorporating washing, draining, and drying functions at the same time.
2. Description of the Prior Art
Conventional washing machines have problems as follows:
Firstly, there is much variation in efficiency, when draining and drying laundry, according to its location within a washing tub. For example, when washing and draining processes have just ended, the laundry contains more moisture where it contacts the inner surface of the washing tub than where it is adjacent to the rotation shaft of the washing tub. Accordingly, the laundry needs mixing before drying.
In addition, since the draining process mainly depends on centrifugal force, which is caused by the rapid revolution of the washing tub, it takes much time for the laundry to recover from a wrinkled state, which has resulted from the revolution.
Besides, since the protrusion member of the washing tub has no hole, the draining process is inefficient. Furthermore, since the laundry is dried with unconditioned air within the washing tub, the drying process is also inefficient.
The present invention is also directed to a washing machine, more strictly, a washing machine capable of using ozone micro-bubbles for washing.
In general, a washing machine rubs laundry with an aqueous solution of a detergent, in particular a surfactant, so that dirt is removed from the laundry due to the activity of the surfactant.
More particularly, the surfactant uses its penetration, emulsification, and dispersion functions to change the surface tension of water, fibers, and dirt so that dirt is removed from the fibers.
However, if such a surfactant is used, it may be drained and cause eutrophication of rivers. Furthermore, since surfactant cannot disinfect germs which breed in clothes, the laundry should be disinfected separately before and after washing.
In an attempt to overcome the above-mentioned problems, a washing machine has been developed which uses ozone.
A conventional ozone washing machine wherein, contrary to conventional washing machines which use a pulsator to generate eddy currents of water and air bubbles for enhanced decomposition of a detergent and for improved washing effect, ozone gas replaces air and is blown into a washing tub for enhanced decomposition of the detergent, improved washing effect, decreased water contamination, and disinfection of germs which breed in clothes.
However, such a washing machine, which has an ozone generator, cannot provide a satisfactory washing effect, because the ozone is not dissolved in washing water with high efficiency.
Meanwhile, it has been proposed to generate air bubbles so that the saponification of washing water is accelerated and the laundry is subject to physical force, which is caused by the air bubbles, for an improved washing action. However, the air bubbles tend to rise to the surface, rather than contact the laundry, because of their big size. Since the laundry cannot contact the air bubbles for a long period of time, the washing action is limited.
In order to overcome this, a washing machine has been developed which uses micro-bubbles.
The micro-bubbles refer to minute bubbles, which are considerably smaller than conventional air bubbles, so that they strongly adhere to the surface of laundry and thus seldom rise to the surface rapidly and disappear. In other words, the micro-bubbles stay in the washing water for a long period of time and strongly maintain the bubble state. Once they adhere to the laundry, they are not easily separated from it.
Korean Patent Application No. 1996-55,685 (the contents of which are hereby incorporated by reference) discloses a conventional micro-bubble type washing machine wherein a washing tub having a pulsator is rotated by a motor in a draining tub having a heater, for washing action. The washing machine comprises: a door hermetically mounted on the washing and draining tubs via packing; an air tube having an end connected to a holding portion of the door by a tubing; a vacuum pump connected to the other end of the air tube; an air cut-off valve hermetically connected to the air tube; an input switch mounted on the holding portion of the door; and a control panel which is adapted to open the air cut-off valve, turn the vacuum pump on, and operate the heat until it receives a predetermined input from the input switch.
Such a micro-bubble type washing machine is made by adding a pressure reducer, which generate a predetermined vacuum pressure, to a fully automatic washing machine, which boils and dries laundry. Accordingly, the washing machine can shorten the time for boiling and drying the laundry, as well as improve the washing action by using micro-bubbles.
However, the micro-bubbles themselves can perform neither disinfection nor sterilization, because they are made of air. Therefore, they have only a physical washing effect but no chemical washing effect. Besides, the micro-bubbles are generated in a vacuum state under an interlock with a pulsator. This is a complicated process.